Method for marking solid material, mark formed by method, and solid material marked according to method

A process of forming an optically non-detectable identification mark (210, 320, 410, 535) in a diamond (200, 300). A mark (210, 320, 410, 535) is formed adjacent an outer surface of an article formed from a diamond material having an intrinsic optical center. The method comprises the steps of: applying, by direct laser writing, an image of a pre-designed identification mark (210, 320, 410, 535) to a region (201, 310, 530) of the diamond at or adjacent to a surface of the diamond (200, 300); wherein the fluorescent background of the diamond material from the intrinsic optical center is suppressed under fluorescence imaging by the identification mark (210, 320, 410, 535) such that, at the region (201, 310, 530) of the diamond (200, 300) to which the mark (210, 320, 410, 535) is applied, the identifiable identification mark (210, 320, 410, 535) that is not optically detectable is visible relative to the fluorescent background. 一种在钻石(200，300)中形成不可光学检测的鉴别标记(210，320，410，535)的工艺。标记(210，320，410，535)被形成在邻近由具有本征光学中心的钻石